Anyone know how light someone has gotten their Brompton?

I see that they offer a ti rear triangle for like $400 and a ti fork for like $200.

I recall an ultralight seatpost option---is it carbon?

What about an ultralight handlebar?

Etc., etc.---what can you quickly get one down to using the fewest fairly standard parts? And working on the major items. And maybe also opting for a singlespeed with one brake, say.

I'm wondering if you can fairly reasonably get down to, say, 15 lbs.

OK, why limit it to Brompton...any other lightweight folders or conversions out there?

--Jeff Potter, http://AllBikeMag.com